MY2002 STi boosting/Turbo issue.Any ideas what to do?
 

I had my car mapped back in July by the awsome JGM.

About a week or so later I notice on gear change the rev's sticking slightly but put it down to me being a big girls blouse on the new power format.

However I think over time I have since adjusted to the rev or boost but lately it has become a lot worse.
Whilst I was at Powerstation a couple of weeks ago Curtis drove my car and the revs jumped up on gear change. I didn't say anything and thought it was his style of driving. He then asked me what power etc and mods I was running. He said he felt it was jumping high in the revs to him to which I agreed etc.

So when we got back Rich had a quick look and suggested the VTA maybe sticking causing the boost to escape on open and then not closing fully. Seemed straight forward enough.

So I stripped the VTA (Forge) down and did notice the large piston was slightly worn. So got the service kit from Forge and changed
x1 large piston
x2 Springs (Blue and small spring)
All rubber seals
And fully oiled with the supplied red oil/grease.

I am still having the problem on gear change. It's not the clutch (as I first thought) and not the driver before you ask. :norty:

I've also checked for leaks around the TMIC. :freak3:

What do you think it could be?
The actuator arm sticking on my VF35? What's the best way to free this up? Abit of WD40
The actuator itself shagged?
Boost solenoid? do I take it off and grease it up with a clean?
Or even the fact the Blue spring is to weak or lower spring to weak. Shoudl I add a shim?


Please can you help as it's making driving a nightmare at the moment when stuck in traffic or when I need to put my foot down to go round slower cars,trucks etc on the carridgeways and motorways.

Steve

Ask the JGM himself, a very nice bloke, and ask if he's around your neck of the woods any time soon !

DunxC

Dunx,

Cheers mate I've had a word with Simon via PM on another forum but would like to try and resolve the problem prior to when I can see him.

My car isn't popping and banging on over run as violent as it used to (added in the map with over run) .

Somethings up. Sods law.

Steve

Update.

Checked the car yesterday. Could not find anything. Greased the actuator arm,throttle linkage etc.
I even got a friend and fellow SN user to have a go to confirm it wasn't my mind.......and sure enough it's still doing it.

One thing I did notice however was that my exhaust inside looks brown/rusty colour rather than black and so fourth!!

Any idea's now.

Steve

No, that's good. Browny-grey type deposits (assuming it's not rust lol) in your exhaust's tail indicates the engine's running a healthy A/F ratio...Well, that goes for spark plug deposits anyway...

...Er, actually thinking about it a bit more, my exhaust's tail gets sooty and I've had a PFC professionally mapped by JGM (plus Lamdba is brand new and working properly, as monitored by my Commander)... So perhaps anything other than a black exhaust could mean the motor's running lean, then? :wonder:

Cheers for the reply buddy.

My car is not throwing any fault codes up at all. I've chaning my oil in the next day or two so will check the plugs at the same time.

Fingers crossed it should be straight forward issue. Hope to see Si on wednesday.

Steve

Possible Sticking Idle Speed Control Valve, if this sticks or changes suddenly it will be like a sidden change of throttle position.

Have a search on North American Subaru Impreza Owners Club as there are a few threads about cleaning them.

try sticking the standard recirc on mate my money is on the dump valve

Have a forge recirc on its way to me in the next day or so.

Hope it is just the vta causing the issue. I'm seeing Simon (JGM) tomorrow so fingers crossed.

Steve

Cheers Scott.
I'm waiting on a price from Cheam Motors on one of these. Should be nice and pricey. D'OH!!

See how it goes matey.

Steve

if its adjustable,set it so its nice and tight and see how it runs,post up how u get one mate always good too know